Thread guides having restricted apertures for use in warp knitting machines

ABSTRACT

There are provided thread guides of novel structure having a protuberance in the plane of the head portion of the thread guide extending into the aperture of the eyelet portion whereby the radius of curvature of a thread passing through the eyelet during the working of the warp knitting machine is substantially increased.

United States Patent [191 Kohl [ THREAD GUIDES HAVING RESTRICTED APERTURES FOR USE IN WARP KNITTING MACHINES [76] Inventor: Karl Kohl, l0 Chlorodont Strasse,

Obertshausen, Germany 6053 [22] Filed: May 29, 1973 [21] Appl. No.: 364,598

[30] Foreign Application Priority Data May 29, 1972 Germany 2226000 [52] US. Cl 66/86 R [51] Int. Cl D04b [58] Field of Search 66/86 [56] References Cited UNITED STATES PATENTS 464,995 12/1891 Roberts 66/86 2,680,959 6/1954 Walford 66/86 Sept. 24, 1974 Primary Examiner-Ronald Feldbaum Attorney, Agent, or FirmOmri M. Behr, Esq.

[5 7] ABSTRACT There are provided thread guides of novel structure having a protuberance in the plane of the head portion of the thread guide extending into the aperture of the eyelet portion whereby the radius of curvature of a thread passing through the eyelet during the working of the warp knitting machine is substantially increased.

4 Claims, 4 Drawing Figures THREAD GUIDES HAVING RESTRICTED APERTURES FOR USE IN WARP KNITTING MACHINES DESCRIPTION OF THE PRIOR ART The aperture of the eyelet portion of thread guides utilized in warp knitting machines is either round or oval. During the operation of the machine the thread utilized in the knitting process passes through the aperture and the direction thereof is turned at one edge. In these conventional thread guides the portion of the aperture contacting the thread presents a concave edge thereto. As a result of this structure, coupled with the necessity of the thread being substantially under tension, the radius of curvature of the thread at this contact point where the thread guide changes its direction, is extremely small. Compression of the filaments of the thread is thus increased. In loosely spun threads the individual filaments will be loosened or abraded, or even pulled up to form slub -like imperfections in the thread due to accumulation of individual fibers. Heretofore, these problems could only be overcome either by reducing the thread tension or by increasing the angle between the thread being fed into the guide and the thread being fed out from it. A further proposed solution has been the use of elongated apertures in the eyelet portion. None of these solutions has proved satisfactory. It would therefore be desirable to provide a thread guide which does not affect the internal tension of the thread or damage its fibers in any way while changing its direction in the conventional manner. Without utilizing excessively large apertures of the eyelet or either reducing the thread tension or the angle between the thread being fed in and the thread being fed out of said thread guides.

SUMMARY OF THE INVENTION The novel thread guides of the present invention are substantially conventional thread guides wherein a protuberance is provided on at least one edge of the eyelet portion of the head. Said protuberance is in the plane of the thread guide and extends into the aperture of the eyelet slightly restricting the area thereof.

DESCRIPTION OF THE DRAWINGS FIG. I is a side elevational view of a portion ofa conventional thread guide showing the manner in which it conventionally turns the thread passing therethrough.

FIG. 2 is a side elevational view of the head portion of a improved thread guide of the present invention.

FIG. 3 is an enlargement of the view of FIG. 2 showing also the increase in the radius of curvature at the turning point of a thread passing therethrough.

FIG. 4 is a side elevational view of a second embodiment of the improved thread guide of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The prior art thread guides illustrated in FIG. 1 comprise a head portion having an eyelet portion 12 with an aperture 14 provided therethrough. During the operation of the thread guide the thread which passes through aperture 14 contacts the inner edge 16 of 12 at 17 whereby thread 20 is bent between infeeding portion 22 and outfeeding portion 23 giving rise to an extremely sharp radius of curvature 24. It is the object of the present invention to increase the radius of curvature at 24 without increasing the angle between portions 22 and 23 of thread 20 and without reducing the normal operative tension in thread 20 which is desirable for efficient operation of the knitting equipment. In the improvement of the present invention head portion 30 comprises an eyelet 32 having an aperture 34 therethrough. In at least one side of the head, eyelet portion 32 is extended inwardly into aperture 34 by means of protuberance 35. It should be noted that the important factor in this improvement is the provision of protuberance 35. The shape of the rest of the circumference of aperture 34 may be varied to suit other requirements of the equipment, that is to say, it may be substantially circular as shown in the prior art of FIG. 1 or substantially oval as shown in FIGS. 2 and 3.

The edge 36 of aperture 34 is substantially perpendicular to the plane of head 30. Nevertheless, the degree of curvature of protuberance 35 is such that thread 20 will ride" upon edge 36 at protuberance 34 in such a manner that the radius of curvature at 24' is substantially greater than the radius of curvature at 24 in the conventional thread guide. This novel structure, having been proposed, it will be clear to those skilled in the art that the actual radius of curvature of protuberance 35, its extension into the central area of aperture 34, that is to say, the area occupied by protuberance 35 which would otherwise constitute aperture 34 and indeed the mathematical description of the curvature of protuberance 35 may be varied to suit the particular requirements of the fabric being produced. Thus, the protuberance 35 can be described as presenting a substantially convex edge into aperture 34 while the remaining portion of edge 36 presents a substantially concave aspect aperture 34. It will be clear from a view of the drawings and this description that the term convex is not intended in its strict mathematical meaning of the outer portion of a regularly circular surface but rather in its broader sense ofa direction ofcurvature which is the reverse of a substantially concave surface. It will therefore be understood that any substantially convex curves such as hyperbolas, parabolas, circles and the like should be considered as falling within the scope of the present invention be subsumed under the general term substantially convex.

FIG. 4 illustrates an embodiment of the present invention which may be considered as a limiting case of the embodiment of FIG. 2. The protuberance 35 has a radius of curvature of infinity, its inner, i.e. aperture edge of 35 may also be defined as lying along a chord drawn across the aperture 34.

I claim:

1. In a thread guide for a warp knitting machine comprising a head portion, said head portion having an eyelet portion, said eyelet portion having an aperture therethrough for the laying of the thread, the improvement comprising at least one protuberance extending into the aperture of said eyelet from one side of said eyelet.

2. In a thread guide of claim 1 the improvement comprising a planar protuberance in the principle plane of the head of said thread guide, extending into said aperture of said eyelet restricting the area of said aper- 4. In a thread guide of claim 3 the improvement comture. prising 3. In a thread guide of claim 2 the improvement coma protuberance having a radius of curvature suffiprising ciently large for the thread to ride on the inner a protuberance presenting a substantially convex 5 edge thereof.

edge into the aperture of said eyelet. 

1. In a thread guide for a warp knitting machine comprising a head portion, said head portion having an eyelet portion, said eyelet portion having an aperture therethrough for the laying of the thread, the improvement comprising at least one protuberance extending into the aperture of said eyelet from one side of said eyelet.
 2. In a thread guide of claim 1 the improvement comprising a planar protuberance in the principle plane of the head of said thread guide, extending into said aperture of said eyelet restricting the area of said aperture.
 3. In a thread guide of claim 2 the improvement comprising a protuberance presenting a substantially convex edge into the aperture of said eyelet.
 4. In a thread guide of claim 3 the improvement comprising a protuberance having a radius of curvature sufficiently large for the thread to ride on the inner edge thereof. 